CRI and beam angle: colour and light distribution

What CRI means

The colour rendering index, usually shown as CRI or Ra, describes how a source renders selected colours compared with a reference. A higher general index usually indicates closer rendering in the test, but a single figure does not describe every aspect of colour quality.

For spaces where colours matter, such as dressing areas, artwork or products on display, compare the manufacturer’s information rather than relying only on the phrase “natural light”. CRI and colour temperature are separate properties.

Narrow or wide beam?

Distance changes the result

The illuminated patch generally grows as the distance from the source increases, while the light reaching the surface changes. The declared angle alone cannot establish the final lux level. For demanding projects, use the manufacturer’s photometric data or ask for a design.

Reduce glare

• Consider where people will look at the fitting, including from a seated position.
• Check whether the light source is directly visible and whether the fitting has shielding or a diffuser.
• Avoid directing strong spots into eyes, reflective screens or shiny surfaces.
• Use distribution and positioning to light the task instead of adding output indiscriminately.

Questions before buying